Tight intake valves 06 YZ450

they're tight..can't even get a gage in there they're so tight.the exhausts are fine.My kids have been riding the bike and I haven't been paying much attention to it until I hopped on it and felt a good lack of compression and it was hard to start..My son said that its been like that for a while..the bike has about 100hrs max..Should I just re-shim it? or are those seats hammered too bad I should just do a head job?

If you have zero clearance, you will need shims more than two sizes (.10mm) thinner than the originals.  That's a bad sign.  You could shim them and see if they will hold that setting.  If they do, you're OK for now, but they will more likely close right back up in short order. 

 

You almost certainly need a valve job.

If you have zero clearance, you will need shims more than two sizes (.10mm) thinner than the originals.  That's a bad sign.  You could shim them and see if they will hold that setting.  If they do, you're OK for now, but they will more likely close right back up in short order. 

 

You almost certainly need a valve job.

Yeah I'm not going to mess around :thumbsup: ..Another question for ya if you don't mind..i kinda know the grim answer to but..I'm sure you know about the counter balancer bearings on the CRFs screwing up the water pump seals..well my cousin just brught me over his bike to change the shaft seals etc..anyway while I have the case off I check the counter balancer gear and shaft and the bearing has play,but at the outer race in the case..the kid is heartbroken..Is there any way to take up that slack without pulling the whole motor apart and changing the case?

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